For years, North Korea has thumped its chest and pumped its fists, shooting ill-fated missiles toward its neighbours and parading its million-strong military with tanks and artillery systems. Now that Kim Jong-il is finally getting the international attention he has craved, the enigmatic leader is rolling the drums of war as Washington steps into the fray.

But President Obama could be walking into the very minefield he has warned against in the past. The same Obama who railed against his predecessor George Bush's "unwise" war in Iraq for wasting US military resources and distracting troops from catching Osama bin Laden, is now helping escalate tensions against North Korea. With Iraq nowhere near a done deal and the war in Afghanistan gaining steam, the president is nonetheless backing moves that could lead to the type of "dumb war" he foreshadowed in 2002, with undetermined length, cost and consequences.

The grim prospect of nuclear war is rearing its ugly head amid growing outrage over the North's alleged sinking of a South Korean naval ship two months ago. Obama threw his full, "unequivocal" support behind Seoul, directing military commanders to link up closely with South Korean counterparts to "ensure readiness and to deter future aggression".

Just as top US diplomat Hillary Clinton toured the region and spoke of a "highly precarious" situation, the Pentagon and South Korea announced plans for joint naval exercises to take place soon in a powerful show of force that would include anti-submarine drills in the Yellow Sea.

Ratcheting up the pressure further, South Korean president, Lee Myung-bak, is redesignating the North as his country's "principal enemy" for the first time since their detente in 2004, cutting off trade ties, denying the North's access to shipping lanes and urging punitive UN measures for the sinking of the Cheonan that killed 46 sailors on March 26. In the same breath, he also took a swipe at his liberal predecessors' "sunshine policy" of reconciliation with the reclusive Stalinist state that aimed to unify the Korean peninsula.

Relations between the two neighbours hit their lowest point in years as Lee pledged to make the North "pay a price" while the power-hungry Kim threatened to retaliate against any sanctions with an "all-out war" and cut its last remaining ties with Seoul. The South, where nearly 29,000 US troops are stationed, is blaring propaganda over the demilitarised zone between the two countries, and the North is threatening to do the same and to destroy Seoul's loudspeakers with artillery shells. All this between two nations still formally at war that share one of the world's most heavily armed borders – US and South Korean troops on one side, the North's huge military on the other. The two sides are just one step short now of a full-scale military strike.

But with China still wavering on planned economic sanctions against Tehran over its nuclear defiance, US officials have to walk a tight rope in obtaining concessions from the Asian powerhouse. China, a major investor in Iran's energy sector, also accounts for about half of all North Korean trade, while South Korea is Pyongyang's second-biggest trading partner. And Washington still has a trade deficit of some $227bn with Beijing.

Clinton, accompanied by some 200 American officials, left China largely empty-handed on North Korea, having obtained no concessions and merely a pledge to "stay in very close consultation". Beijing, a permanent member of the UN security council, is showing no signs of budging from its highly cautious and restrained response as Seoul and Washington pressure China to back efforts to bring the Cheonan issue before the council. Such a move could further ostracise Pyongyang, and China appears unwilling to do so for now.